Glossary of International Calling Terms

International calling terms are many and varied terms. As a result, the terminology used when talking about international calling, international phone numbers, and international telephone service can be very confusing.

While many international calling terms are used commonly worldwide, there are also many other terms that used only in certain regions or certain countries. As a result, it is easy to get confused about things.

We ourselves still get confused when we come across too many terms like IAC, STD, SDCA, and ISD in the same sentence.

The glossary of terms below is only a very rough effort to list and define some of the more commonly used terms. The list is by no means comprehensive. And the definitions offered may not even be accurate for all countries and situations, but hopefully they are correct for most circumstances.

Area code - A dialing code that designates a certain geographic region within a country, such as a city or state. Within each area code, local subscriber numbers are assigned to individual landline and mobile phones. Area codes may overlap each other - in other words, the same geographic region may have more than 1 applicable area. Area codes are also known as: STDs.

Calling card - A way to buy telephone services based on pre-paid purchasing of minutes. Pre-payment is made based on advertised per minutes rates plus varying additional charges such as connection fees and maintenance fees. aka phone card.

Cellular phone - Same as mobile phone. Becoming less popular over time. 'Cellular' refers to an underlying construct of mobile telephony which is that calls are managed based on physically defined topography of 'cells' determined by the placement of transmission/reception towers.

Landline phone - Refers generally to telephone service delivered to specific physical location via a fixed telecommunications network (i.e., via a wired network). The opposite of mobile phone service which allows a phone to receive calls while moving from place to place.

Local subscriber number - The specific phone number assigned to an individual landline or mobile phone. Such number refers generally to the part of a phone number after the area code. Varies in length between countries and even within countries.

Local virtual number - One of two main types of virtual number where the inbound caller dials to a local subscriber number. Such calls are generally free to the caller if the local number is within their area code or if the caller has flat-rate nationwide service (e.g., on many mobile plans). Any inbound calling charges are borne by the caller. The other type of virtual number is a toll-free virtual number.

Mobile phone - A kind of phone or phone service which allows a phone to receive calls while moving from place to place. Such phone service works by sending signals wirelessly through the air via transmitters and receivers attached to cell towers. aka cellular phone, cell phone, and wireless phone.

SIP - SIP, an acronym for 'session internet protocol' is a specific type of technology used for managing telephone calls made over the internet. In other words, SIP is a specific type of VoIP internet telephony. Click here for more information on SIP

Toll-free virtual number - One of two main types of virtual number where the inbound caller dials to a toll-free number from a wide long distance calling area (usually a country). Any inbound calling charges are borne by the virtual number subscriber, not the caller. The other type of virtual number is a local virtual number.

Virtual phone number - A phone number purposefully used to forward calls to another phone number. Usually used in conjunction with a VoIP internet calling service as a way to reduce costs to inbound callers. For instance, an Indian company might buy a virtual number in the United States and then forward incoming calls to an India location so it's customers don't have to incur international calling charges. There are two main types of virtual number: local virtual number and toll-free virtual number.

VoIP - VoIP stands for Voice over Internet Protocol and refers to a relatively new technology that enables you to make telephone calls over the internet. Traditionally, phone calls have been carried over dedicated telephone switching networks - either fixed line wired networks using copper wires and fiber optics or over mobile networks using airwaves and cellular towers. With VoIP telephony, calls are routed over the same communications network that carries regular internet traffic for websites and such. Click here for more on VoIP internet telephony.

VoIP calling card - A kind of calling card that is specifically delivered using VoIP technology. However, since most calling card companies utilize VoIP to deliver calls (even if they don't advertise as such), this may not be a terribly meaningful descriptor.

VoIP phone - Generally used to describe a specialized type of phone that allows you to make VoIP internet calls. Certain models have dual function as a normal landline phone as well. In addition, many mobile smartphones can be configured to work with a VoIP service as well as normal mobile service.